With the continuous development of display technology, stereoscopic display has become a major trend in the display technology. The fundamental principle of stereoscopic display is in that parallax images result in stereoscopic display, that is, the image for left eye is seen by the left eye of a viewer and the image for right eye is seen by the right eye of the viewer. The image for left eye and the image for right eye are a pair of stereoscopic images with parallax.
A way to achieve stereoscopic display is serial type, i.e., at a first time, the image for left eye is displayed on the display, and then only the left eye of the viewer can see the displayed image; and at a second time, the image for right eye is displayed on the display, and then only the right eye of the viewer can see the displayed image. Due to the persistence of vision on the human eye retina, people will feel that both the left eye and the right eye see the image for left eye and the image for right eye respectively and simultaneously to produce stereoscopic perception.
Another way to achieve stereoscopic display is parallel type, i.e., at the same time, the image for left eye is displayed by a portion of pixels on the display and the image for right eye is displayed by another portion of pixels on the display, and by means of grating, polarized glasses, etc., the display of the portion of pixels can be seen only by the right eye, and the display of another portion of pixels can be seen only by the left eye, thereby producing stereoscopic perception.
In order to present a better stereoscopic visual effect, currently it is usual to use polarized glasses to achieve stereoscopic display. The basic mechanism of the display technology is to arrange a device in front of the display panel to adjust the polarization direction of the outgoing light. Such a device may be a retardation plate, a liquid crystal cell, or other devices which can adjust the polarization direction of light emitted from pixels to be different.
The display principle that the retardation plate achieves stereoscopic display is shown in FIG. 1. On the display panel 7′, when a row of pixels display the image for right eye, an adjacent row of pixels display the image for left eye; there exists a retardation plate 5′ arranged in front of the display panel 7′, and when one row achieves a λ/2 delay, an adjacent row achieves zero delay, so that on the output image 6′, the polarization direction of light emitted from pixels undergoing the λ/2 delay rotates 90°. Thus, when wearing polarized glasses in which polarization directions of right and left eyes orthogonal to each other, the right eye only sees light emitted from pixels displaying the image for right eye, and the left eye only sees light emitted from pixels displaying the image for left eye, resulting in stereoscopic visual effect.
Among a variety of technologies using polarized glasses to achieve stereoscopic display, a retardation plate (pattern retarder) technology is most favored. Its basic mechanism is as follows: a retardation plate is accurately aligned on a display panel, and the retardation plate is attached on the display panel; on the retardation plate, different regions can achieve different phase delays, so that light from different pixels output in different polarization directions and a viewer wearing polarized glasses can see the 3D effect.
As shown in FIG. 2, a method for fabricating a retardation plate in the prior art is as follows:
(1) applying optical alignment material 2′ on the substrate 1′;
(2) placing a mask plate 3′ above the optical alignment material 2′;
(3) through the mask plate 3′, irradiating a part of the optical alignment material 2′ not blocked by the mask plate 3′ by polarized light 4′ to cure by exposure;
(4) removing the mask plate 3′ and curing the remainder of the optical alignment material 2′ by exposure;
(5) applying reacting material to perform alignment curing.
In the actual fabricating process of the retardation plate, it is required to use the mask plate, resulting in high fabrication cost, and the alignment accuracy is not high.